Black Sigatoka (IMAGE) University of Exeter Caption Dark streaks on a banana leaf caused by toxins released from the fungus when they react with sunlight. Credit Dan Bebber Usage Restrictions This image may only be used with reports of this research License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.